Not long ago, horror movies were fairly predictable fare: You had your unstoppable psycho, your bevy of half-naked women, several buckets of blood and an ending that promised a sequel.

But today? That old formula seems so 20th century.

The horror resurgence of recent years has been wildly diverse, encompassing a range of artful, innovative, even socially provocative films. The different cinematic styles, from the historical realism of “The Witch” to the laptop-based “Unfriended,” are as varied as the subject matter, which might tackle female sexuality (”Jennifer’s Body”), racism (”Get Out”) or even the American justice system (”The Purge”). What’s more, as the genre achieves that magic combination of critical praise and big box-office, it is attracting major talents: Vera Farmiga, Toni Collette and John Krasinski are a few examples. Horror also got a rare Oscar moment earlier this year when “Get Out” earned a nod for best picture.

In short, horror is achieving a credibility it hasn’t had since the days of “Rosemary’s Baby” and “The Exorcist.” Those classics still rank high on any all-time greats list, of course, but maybe it’s time to take stock of more recent titles that are pushing horror to new heights of acclaim and popularity. Here are the 21 best horror films — so far — of the 21st century.

1. “Hereditary” (2018): After her mother’s death, Annie, an obsessive artist (Toni Collette), suspects that her recent misfortunes may stem from her recently deceased mother. If that sounds like familiar territory, be warned: Ari Aster’s riveting debut feature goes where most movies wouldn’t think to go. Combining inventive camerawork, unspeakable tragedies and an excellent cast (including Gabriel Byrne, Alex Wolff and newcomer Millie Shapiro), “Hereditary” is horror’s new high water mark.

2. “Get Out” (2017): Jordan Peele’s debut film about a young black man (Daniel Kaluuya) who meets his white girlfriend’s parents became not just a major hit but the Movie of the Moment. Poking fun at white hypocrisy and black paranoia at a time of heightened racial rancor, the movie found an entertaining way — part horror, part satire — to address a difficult and discomfiting issue. “Get Out” already seems to be paving the way for a new wave of indie black cinema, from the surreal comedy “Sorry to Bother You” to the rap-themed drama “Blindspotting.”

3. “Paranormal Activity” (2009): Not since “The Blair Witch Project” has a horror movie done so much with so little. Set in a haunted McMansion, “Paranormal Activity” uses flickering lights, self-slamming doors and other un-special effects to build a hair-raising sense of tension. Shot for $15,000, Oren Peli’s film earned $193 million, spurred five sequels and helped turn the Blumhouse horror-studio into the powerhouse behind “Split,” “The Purge,” “Get Out” and many others.

4. Black Swan” (2010): Natalie Portman won an Oscar for portraying a mentally unraveling ballerina in Darren Aronofsky’s deliriously weird masterpiece. For such a freaky film, “Black Swan” became a $329 million hit and earned four other Oscar nods, including best picture.

5. “Let The Right One In” (2008): John Ajvide Lindqvist’s novel about a 12-year-old boy and the vampire girl next door has been adapted twice. This Swedish original is a standout: a ghastly and mournful allegory of childhood. Heart-tugging performances from Kare Hedebrant as mortal Oskar and Lina Leandersson as his vampire beloved.

6. “Let Me In” (2010): The American version of the Lindqvist story, starring Chloe Grace Moretz, is slightly jazzed up with bloody effects. Still, it’s uncommonly pensive, bleak and beautiful. It’s just about, er, neck and neck with the original.

7. “The Cabin In The Woods” (2012): Drew Goddard’s Russian nesting-doll of a movie, about two guys in a control room who manipulate humanity, is a mischievous mindblower without a single predictable moment. A modest hit that should have been a blockbuster.

9. “The Witch” (2015): Anya-Taylor Joy’s breakout role came in this beautifully crafted period-piece about an American Colonialist girl whose family begins blaming her for their misfortunes. Exceptionally spooky, with a strange, hypnotic ending.

10. “A Quiet Place” (2018): John Krasinski stars in his own directorial debut as a man trying to protect his family from alien creatures that hunt by sound. This is 90 solid minutes of try-not-to-scream moments, with barely a word of spoken dialogue — a tremendous feat.

12. Split” (2016): A young woman (Anya Taylor-Joy) is kidnapped by a mentally ill man (James McAvoy) who has 23 personalities. M. Night Shyamalan’s surprise comeback was a secret sequel to his hit “Unbreakable,” and now it has spawned another film, “Glass,” due for release in January.

13. “What Lies Beneath” (2000): Harrison Ford and Michelle Pfeiffer are a married couple whose lakeside house is haunted by a drowned woman’s ghost. Some 20 years on, this Robert Zemeckis film might feel a little old-fashioned, but it’s a great Gothic chiller with an A-list cast.

14. “It” (2017): This big-screen adaptation of Stephen King’s novel — about a clown who preys on children — was a critical and commercial smash. Like “Stand By Me,” “It” has an emotional core that feels as strong as the scares.

15. “Saw” (2004): Gratuitously gross, morally bankrupt, aesthetically anemic — say what you will, this gory tale of a sadistic serial killer gave us the term “torture porn” and dominated horror the way “Halloween” did 40 years ago. Eight films on (“Jigsaw” came out last year), we’re still getting splattered.

16. “Drag Me To Hell” (2009): A loan officer (Alison Lohman) turns down an elderly woman who blasts her with a curse. Sam Raimi’s last horror film (at least to date) is a darkly funny fable about greed and selfishness, with an uproariously good finale.

18. “Truth Or Dare” (2018): During spring break in Mexico, several college friends play a well-known drinking game, only to find that they must keep playing — or die. The idea of a haunted game feels somewhat new, and the various deaths have a fiendish irony. A jaunty little body-count flick.

19. “The Last Exorcism” (2010): A fraudulent preacher (Patrick Fabian) encounters a “possessed” girl (Ashley Bell) in the backwoods of Louisiana. It’s an intelligent twist on an old theme; inspired by the 1972 documentary “Marjoe.”

20. “Unfriended” (2014): The ghost of a suicidal teenager preys on her classmates during a group Skype call. It’s a clever update of the found-footage genre, with everything unfolding on a computer screen. It also raises a very 21st-century question: Might this movie feel even scarier if you watched it on a laptop?

21. “The Conjuring” (2013): Horror went classy with this Warner Bros. production starring Oscar nominee Vera Farmiga (“Up in the Air”) and Patrick Wilson as paranormal investigators Lorraine and Ed Warren. Low on bloodshed, long on ambience. The quality has remained mostly high over the six-film franchise.